SNEERING: James Holmes’ apartment was literally a minefield, laden with explosives wired to kill anyone who entered. Photo: AP

Officials use a waterfilled container to short-circuit bombs. (AFP/Getty Images)

Officials use a waterfilled container to short-circuit bombs. (
)

Accused mass-murderer James Holmes spent three weeks rigging his modest apartment as an explosives-laden death trap meant to massacre responding law- enforcement officers, sources said yesterday.

“Make no mistake, this apartment was designed . . . to kill everyone who entered it,” said furious Aurora Police Chief Dan Oates, a former NYPD chief.

“If you think we’re angry, we sure as hell are angry. There is no question what the intent was behind whoever designed that device: to kill whoever opened that door.”

The apartment was littered with gasoline-filled explosive devices connected by trip wire to a central control panel, law-enforcement sources told The Post. There were about 30 homemade bombs in the 800-square-foot apartment, according to the Denver Post.

Meanwhile, a second man was named a “person of interest” by cops, according to a report.

The man is also a student at the same school where Holmes was a doctoral candidate — and someone made a call from his phone threatening violence if Holmes was not released, Fox 31 television in Denver said.

The man’s neighbors said a SWAT team and other cops have been at his home for the past two days.

A later report said the man was an associate of Holmes and was questioned last night, ABC 7 Denver said. The person was picked up after the threat was traced via an electronic communication through a router at the man’s home, the station said.

It is not believed he had any role in the attack.

Meanwhile, the alleged killer was cooling his heels in an Aurora jail while a joint FBI-police team spent nearly all day yesterday cautiously diffusing the madman’s minefield, finally announcing in the early evening that all the hazards had been removed.

Authorities said that Holmes slaughtered 12 moviegoers and injured another 58, seven of whom were still hospitalized in critical condition as of last night.

Holmes allegedly unleashed the carnage at the midnight premiere of “The Dark Knight Rises” — bursting through an emergency exit and filling the packed theater with noxious gas before opening fire with three different guns. He wore body armor from head to toe.

Holmes, who declared himself “The Joker,” and even laughed to cops like Batman’s archenemy, admitted that his apartment was rigged for maximum damage.

“What we’ve seen here is evidence of some calculation and deliberations,” Oates said.

A source added that if the explosives went off, “It’s safe to say that whole building would have burned.”

During yesterday’s operation at Holmes’ three-storybuilding, officers used water to short circuit a control panel that was wired to some of the ball-shaped gasoline containers, sources said.

They also used a “water shot” for a controlled detonation of one explosive device rigged to a trip wire at the front door, another source said. The water prevented a fireball.

“Although not certain, we are hopeful that we have eliminated the remaining major threats,” Aurora police Sgt. Cassidee Carlson said.

“It went very, very well,” Jim Yacone, FBI special agent-in-charge, said of the potentially catastrophic job. “It was an extremely dangerous environment. ”

Officials were removing all of the devices from the apartment and transporting them last night by sand truck to a disposal area.

A man in an ATF shirt was spotted measuring a poster on Holmes’ wall for a DVD called “Soldiers of Misfortune.”

The top-floor apartment is four miles from the scene of the bloodbath. Residents in Holmes’ building and four adjacent residential complexes were first evacuated just after Friday’s carnage.

A building manager and a resident said Holmes was hunting for apartments in the area within the past two to three weeks. In was unclear if he planned to rig those with devices also, or thought he could move there after the massacre.

Holmes had worked as a camp counselor in 2008.

Randy Schwab, director of Camp Max Straus, told the Los Angeles Times that Holmes was responsible for “the care and guidance of a group of approximately 10 children.”

The twisted fiend’s mother is an usher at Penasquitos Lutheran Church in San Diego, according to a parishioner there. His father was said to have flown to Denver to see his son.

About 30 of Holmes’ neighbors were initially taken to a makeshift shelter at the Aurora Central HS gym for food and shelter from the 90-plus degree heat, Red Cross spokeswoman Melinda Epp said.

“He had to have planned this for a while to get everything he’s gotten done. It makes the neighbors angry around here,” said Joanne Southard, the manager of two apartment complexes next to Holmes’ house.